Has Hell already been created? Does it exist now?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Hell and Paradise already exist. This is supported by the Quran, the Sunnah and the consensus of Muslim scholars:

Allaah the Almighty Says (what means): {The Fire, they are exposed to it morning and evening. And the Day the Hour appears [it will be said], "Make the people of Pharaoh enter the severest punishment.".} [Quran 40:46]

The Messenger of Allaah, sallallaahu ‘alayhi wa sallam, saw ‘Amr ibn Lahiy in Hell. [Al-Bukhari and Muslim]

When Allaah the Almighty created Hell (before creating humans), he ordered Jibreel (Gabriel) to go and look at it. [Abu Daawood, At-Tirmithi and others]

There are also many other relevant proofs.

Allaah Knows best.